Data privacy is important to the security of our society, and enabling authorized users to query this data efficiently is facing more challenge. Recently, blockchain has gained extensive attention with its prominent characteristics as public, distributed, decentration and chronological characteristics. However, the transaction information on the blockchain is open to all nodes, the transaction information update operation is even more transparent. And the leakage of transaction information will cause huge losses to the transaction party. In response to these problems, this paper combines hierarchical attribute encryption with linear secret sharing, and proposes a blockchain data privacy protection control scheme based on searchable attribute encryption, which solves the privacy exposure problem in traditional blockchain transactions. The user's access control is implemented by the verification nodes, which avoids the security risks of submitting private keys and access structures to the blockchain network. Associating the private key component with the random identity of the user node in the blockchain can solve the collusion problem. In addition, authorized users can quickly search and supervise transaction information through searchable encryption. The improved algorithm ensures the security of keywords. Finally, based on the DBDH hypothesis, the security of the scheme is proved in the random prediction model.
The exploitation of efficient and economical electrocatalysts for hydrogen evolution reaction (HER) is of exceeding interest in renewable cleanenergy technologies. Herein, the facile solvothermal reaction of S and chromic acetate in ethylenediamine (en) achieved a novel organic hybrid chromium sulfide [Cr 4 (μ 3 -S) 4 (en) 4 (SH) 4 ]•0.25H 2 O (1), which offers a new type of antiferromagnetic cubanelike chromium sulfide cluster with σ-donor en ligands. 1 was utilized in combination with Ni nanoparticles and porous Ni foam (NF) to fabricate a Ni/1/NF electrode as an efficient cathodic catalyst, indicating excellent electrocatalytic property toward HER.
Abstract. As a public basic required course of college, status of Higher Mathematics is of vital significance. However, the theory is too difficult to understand, most students think that math is useless so that they are not interested in higher mathematics. Today, MATLAB is one of the most developed software packages available. The purpose of this paper is to enable most students and particularly non-math majors to understand how to use MATLAB correctly in solving their problems of interest. In this paper, we focused on understanding the fundamental mathematical concepts and mastering problem-solving skills with the help of MATLAB and skip some tedious derivations. We found that by taking the MATLAB as an auxiliary and applying it into the teaching of higher mathematics, mathematical problems would be easy to solve. In this paper, almost every algorithm is followed by example MATLAB code with a friendly interface, so that students can easily modify the code to solve practical problems.
Abstract-In this article, we made a further studies on the false-assignments of Boolean Function, which made us not only get the theory evidence by using false-assignments to judge the function's elusiveness, but also verify the result's effectiveness by using specific function.
which is an improvement in the conclusion of the theorem. In the end, we illuminate the practicability of the improved mean value theorem for integral with two examples as follows.
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